System stops booting after "GEOM_MIRROR: Force device gm0 start due to timeout."

The title of the thread pretty much says it all: my FreeBSD 8.0-RELEASE system stops booting after I get the following message from GEOM_MIRROR:

Code:

GEOM_MIRROR: Force device gm0 start due to timeout.

I cannot seem to find any help through Google, or by searching this forum.

I took the server down cleanly after a power outage yesterday (the system was still running off of a UPS) and today, when I went to power it back up, I got this message. And, like I said, the system literally stops booting after that message gets printed - but the system is not locked-up, it still responds to ACPI switches and the keyboard (to an extent).